PMID- 29752618
OWN - NLM
STAT- MEDLINE
DCOM- 20190318
LR  - 20190318
IS  - 1573-9546 (Electronic)
IS  - 1573-9538 (Print)
IS  - 1573-9538 (Linking)
VI  - 14
IP  - 3
DP  - 2018 Sep
TI  - Tritium-labeled agonists as tools for studying adenosine A(2B) receptors.
PG  - 223-233
LID - 10.1007/s11302-018-9608-5 [doi]
AB  - A selective agonist radioligand for A(2B) adenosine receptors (A(2B)ARs) is 
      currently not available. Such a tool would be useful for labeling the active 
      conformation of the receptors. Therefore, we prepared BAY 60-6583, a potent and 
      functionally selective A(2B)AR (partial) agonist, in a tritium-labeled form. 
      Despite extensive efforts, however, we have not been able to establish a 
      radioligand binding assay using [(3)H]BAY 60-6583. This is probably due to its 
      high non-specific binding and its moderate affinity, which had previously been 
      overestimated based on functional data. As an alternative, we evaluated the 
      non-selective A(2B)AR agonist [(3)H]NECA for its potential to label A(2B)ARs. 
      [(3)H]NECA showed specific, saturable, and reversible binding to membrane 
      preparations of Chinese hamster ovary (CHO) or human embryonic kidney (HEK) cells 
      stably expressing human, rat, or mouse A(2B)ARs. In competition binding 
      experiments, the AR agonists 2-chloroadenosine (CADO) and NECA displayed 
      significantly higher affinity when tested versus [(3)H]NECA than versus the 
      A(2B)-antagonist radioligand [(3)H]PSB-603 while structurally diverse AR 
      antagonists showed the opposite effects. Although BAY 60-6583 is an A(2B)AR 
      agonist, it displayed higher affinity versus [(3)H]PSB-603 than versus 
      [(3)H]NECA. These results indicate that nucleoside and non-nucleoside agonists 
      are binding to very different conformations of the A(2B)AR. In conclusion, 
      [(3)H]NECA is currently the only useful radioligand for determining the affinity 
      of ligands for an active A(2B)AR conformation.
FAU - Hinz, Sonja
AU  - Hinz S
AD  - PharmaCenter Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, An der 
      Immenburg 4, 53121, Bonn, Germany.
FAU - Alnouri, Wessam M
AU  - Alnouri WM
AD  - PharmaCenter Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, An der 
      Immenburg 4, 53121, Bonn, Germany.
FAU - Pleiss, Ulrich
AU  - Pleiss U
AD  - Bayer Pharma AG, Friedrich-Ebert-Strasse 217-333, 42117, Wuppertal, Germany.
FAU - Muller, Christa E
AU  - Muller CE
AD  - PharmaCenter Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, An der 
      Immenburg 4, 53121, Bonn, Germany. christa.mueller@uni-bonn.de.
LA  - eng
PT  - Journal Article
DEP - 20180511
PL  - Netherlands
TA  - Purinergic Signal
JT  - Purinergic signalling
JID - 101250499
RN  - 0 (Adenosine A2 Receptor Agonists)
RN  - 0 (Aminopyridines)
RN  - 0 (BAY 60-6583)
RN  - 0 (Receptor, Adenosine A2B)
RN  - 10028-17-8 (Tritium)
RN  - 35920-39-9 (Adenosine-5'-(N-ethylcarboxamide))
SB  - IM
MH  - *Adenosine A2 Receptor Agonists/pharmacology
MH  - Adenosine-5'-(N-ethylcarboxamide)/pharmacology
MH  - Aminopyridines/pharmacology
MH  - Animals
MH  - CHO Cells
MH  - Cricetinae
MH  - Cricetulus
MH  - Humans
MH  - Mice
MH  - Protein Conformation
MH  - Radioligand Assay/*methods
MH  - Rats
MH  - Receptor, Adenosine A2B/*chemistry
MH  - Tritium
PMC - PMC6107469
OTO - NOTNLM
OT  - Adenosine A2B receptor
OT  - Agonist radioligand
OT  - Kinetics
OT  - Radioligand binding
OT  - [3H]BAY 60-6583
OT  - [3H]NECA
COIS- CONFLICT OF INTEREST: The authors declare that they have no conflict of interest. 
      ETHICAL APPROVAL: This article does not contain any studies with human 
      participants or animals performed by any of the authors.
EDAT- 2018/05/13 06:00
MHDA- 2019/03/19 06:00
PMCR- 2018/11/11
CRDT- 2018/05/13 06:00
PHST- 2018/01/08 00:00 [received]
PHST- 2018/04/27 00:00 [accepted]
PHST- 2018/05/13 06:00 [pubmed]
PHST- 2019/03/19 06:00 [medline]
PHST- 2018/05/13 06:00 [entrez]
PHST- 2018/11/11 00:00 [pmc-release]
AID - 10.1007/s11302-018-9608-5 [pii]
AID - 9608 [pii]
AID - 10.1007/s11302-018-9608-5 [doi]
PST - ppublish
SO  - Purinergic Signal. 2018 Sep;14(3):223-233. doi: 10.1007/s11302-018-9608-5. Epub 
      2018 May 11.